Crohn's disease is an inflammatory disorder of the gastrointestinal (GI) tract, likely associated with a hyperactive immune response to commensal bacteria and mucosal damage. The treatments for Crohn's disease and inflammatory bowel diseases (IBDs) in general have the potential for serious side effects. New approaches for controlling the progression of these diseases are needed. A treatment that works at the mucosal surface, to modulate mucosal inflammation and associated GI damage to prevent or reduce disease severity, would change the quality of life for millions worldwide. A recently developed polysaccharide derivative (PAAG) acts at the mucosal surfaces to facilitate a reduction of inflammation and enhanced barrier function by reducing GI damage. Understanding how PAAG directly modulates key mediators in innate host defense and mucosal integrity, such as toll-like receptors (TLR's) and similar pathways is essential in providing a well-tolerated treatment alternative. In vitro cell based assays will assess the influence of PAAG on TLR activation by pathogen associated molecular patterns (PAMP's) and damage associated molecular patterns (DAMP's) in human GI cells via colorometric signal transduction reporter-gene based assays and pathways, focused qPCR analysis. The effectiveness of oral PAAG treatment in the adoptive transfer model of chronic colitis in vivo will be assessed and compared to confirm prior study success in acute GI inflammatory animal models. Genes influencing the therapeutic response of PAAG in the mouse colon, compared to vehicle control will be identified following hypotheses driven gene expression analysis guided by prior gene expression analysis in related models of GI inflammation. Fecal and serum markers, indicative of the level of GI damage and inflammation, will be measured via ELISA and further validate the effectiveness of PAAG treatment. Molecular methods will determine if microbiome diversity is influenced by treatment with PAAG. The goal of this study is to optimize PAAG dosage and elucidate specific mechanisms that facilitate efficacious disease treatment. Successful outcomes will guide further development of this product toward clinical trials of a safe and effective treatment for Crohn's disease and related IBD's.